Regulation of adhesion molecule expression by CD8 T cells in vivo. II. Expression of L-selectin (CD62L) by memory cytolytic T cells responding to minor histocompatibility antigens.

Activation of murine T cells by Ag or mitogens results in changes in the expression of several cell-surface adhesion molecules that alter the way in which these cells migrate and localize in tissues in vivo. As naive CD8 precursor cells in lymph nodes (LN) differentiate into effector CTL in response to a skin allograft, they up-regulate their expression of Pgp-1 (CD44), VLA-4, and LFA-1 (CD11a/18), while down-regulating L-selectin (CD62L). All cytolytic activity is therefore present in this minor population of L-selectin- Pgp-1high LN T cells.

Differential activation-dependent regulation of integrin function in cultured human T-leukemic cell lines.

T lymphocytes isolated from human peripheral blood express beta 1 (VLA) and LFA-1 integrins, but strong binding to integrin ligands occurs only after the delivery of an activation stimulus to the T cell. To gain further insight into activation-dependent regulation of integrin function, we have analyzed integrin activity on three different T-leukemic cell lines: Jurkat, CEM, and H9. This analysis shows important mechanistic differences in integrin regulation.

Distinct divalent cation requirements for integrin-mediated CD4+ T lymphocyte adhesion to ICAM-1, fibronectin, VCAM-1, and invasin.

Integrins are a large family of cell surface receptors that mediate the adhesion of cells to other cells and to components of the extracellular matrix. Various divalent cations, particularly Ca2+ and Mn2+, have been shown to modulate the functional activity of many different integrins expressed on a wide variety of cell types. In this study, we have characterized the divalent cation requirements for the adhesion of human peripheral CD4+ T cells to four distinct integrin ligands: the alpha 4 beta 1 and alpha 5 beta 1 ligand fibronectin, the alpha 4 beta 1 ligand VCAM-1, the LFA-1 ligand ICAM-1, and the alpha 4 beta 1 bacterial ligand invasin.

Regulatory mechanisms underlying T cell integrin receptor function.

Adhesion molecules allow lymphocytes to interact with and respond to the extracellular environment. Since these interactions must be essentially transient in nature, the function of lymphocyte adhesion molecules must be precisely regulated. Studies of integrin receptors vividly illustrate the various mechanisms by which the function of these adhesion molecules can be regulated.

Regulation of adhesion molecule expression by CD8 T cells in vivo. I. Differential regulation of gp90MEL-14 (LECAM-1), Pgp-1, LFA-1, and VLA-4 alpha during the differentiation of cytotoxic T lymphocytes induced by allografts.

A variety of adhesion molecules regulate the traffic and tissue localization of lymphocytes in vivo by mediating their binding to vascular endothelial cells. The homing receptor gp90MEL-14 (gp90), also known as LECAM-1 or L-selectin, mediates the adhesion of lymphocytes to specialized high endothelial venules in lymph nodes (LN) and is the primary molecule regulating lymphocyte recirculation and homing to LN, whereas other adhesion molecules have a major role in the localization of lymphocytes in inflammatory sites. We used four-color flow cytometric analysis to examine the regulation of adhesion receptor expression on LN CD8 T cells responding to skin allografts in vivo.

Immune response to a murine coronavirus: identification of a homing receptor-negative CD4+ T cell subset that responds to viral glycoproteins.

The lymphocyte proliferative response to mouse hepatitis virus, strain JHM (MHV-JHM), a well-described cause of chronic and acute neurological infections, has been studied using vaccinia virus recombinants expressing individual MHV proteins. The surface (S) and transmembrane (M) glycoproteins were the most active proteins in causing proliferation of lymphocytes isolated from immunized adult mice, whereas lymphocytes from persistently infected mice proliferated only in response to the S protein. The cells from immunized mice which proliferated most actively in response to MHV were positive for the CD4 antigen and secreted interferon-gamma.

Amplification for listeners with steeply sloping, high-frequency hearing loss.

Two experiments were conducted to determine the effects of various upper cutoff frequencies on performance of listeners with steeply sloping, high-frequency hearing loss. The upper cutoff frequency of individually prescribed responses was systematically adjusted to 0.71, 1.

Laparoscopic evaluation of acute abdominal pain.

It is often difficult to tell which patients with acute abdominal pain will require surgery. We studied 79 patients with acute abdominal pain who were thought likely, though not unequivocally, to have abdominal problems requiring surgery. All underwent laparoscopy and only 27 subsequently required open laparotomies.

Biocompatibility of the central electroauditory prosthesis and the human cochlear nuclei.

Previous studies from the House Ear Institute have reported the possibility of sound sensation from the central electroauditory prosthesis (CEP) implanted in patients during removal of bilateral acoustic neuromas. This study describes histologic features of tissues formed around a CEP that was removed due to infection in the area of the electrical plug on the external surface of the skull. We found a layer of compact collagen tissue around the CEP.

Electrical stimulation of the auditory brain stem structure in deafened adults.

Electrical stimulation of the cochlear nuclear complex in the brain stem was first accomplished in a female adult deafened by bilateral acoustic tumors. The central electroauditory prosthesis (CEP) was surgically placed at the time of the second tumor removal. The patient has now been receiving electrical stimulation for 5 years.

Electrical stimulation of cochlear nucleus in man.

Auditory percepts can be produced by electrical stimulation of the cochlear nucleus in man. The ability to locate accurately and stimulate selectively the cochlear nucleus after removal of an acoustic schwannoma was confirmed in this patient. The surgical approach, electrode design, and a discussion of the results and concerns of electrical stimulation are reviewed.

Nephrogenic adenoma.

Nephrogenic adenoma is an uncommon, benign, apparently metaplastic response of urothelium to chronic infection or irritation. Endoscopically, these lesions easily can be mistaken for malignant tumors, and their scarcity only heightens the possibility of this error. A case report of nephrogenic adenoma accompanied by endoscopic photographs is presented to improve awareness and avoid inappropriate therapy.

Nuclear accidents.

A nuclear accident with radioactive contamination can happen anywhere in the world. Because expert nuclear emergency teams may take several hours to arrive at the scene, local authorities must have a plan of action for the hours immediately following an accident. The site should be left untouched except to remove casualties.

Late complications of abdominal aortic grafting: urologic aspects.

After an abdominal aortic operation late suture line failure with hemorrhage and false aneurysm formation can produce symptoms and/or findings of urologic disease. The urologist should be aware of the non-urologic implications in such instances.